Method and apparatus for surface strengthening of blisk blades

Abstract

For surface strengthening of blisk blades, a blade area of the blisk is completely inserted into a water bath ( 13 ), and a multitude of high-pressure water jets are injected into the water bath which are directed bilaterally and essentially vertically—and opposite to each other—to both blade sides. Cavitation bubbles imploding near the blade surface that are generated in the water bath on the periphery of the high-pressure water jets to produce micro jets upon imploding, exerting an effect on the blade surface, creating plastically formed depressions without sharp edges. An apparatus for performing the method includes a container ( 3 ), a jetting unit ( 6 ) having parallel spaced apart water-jet tubes ( 4 ) with nozzle openings connected to a high-pressure water conduit ( 5 ) to produce the high-pressure water jets.

What is claimed is:  
     
       1. A method for surface strengthening of blisk blades, comprising:
 providing a container at least partially filled with a liquid to provide a liquid bath for receiving a blisk blade; 
 inserting at least a portion of a blisk blade to be surface strengthened into the liquid bath; 
 providing a jetting unit having a pair of parallel spaced apart liquid jet tubes for positioning on opposite sides of the blisk blade, each connected to a supply of high-pressure liquid, each liquid jet tube having a plurality of nozzle openings equidistantly disposed along a longitudinal direction of the liquid jet tube to produce high-pressure liquid jets penetrating the liquid bath in a direction toward a surface of the blisk blade, the nozzle openings of each of the pair of liquid jet tubes being aligned with and directed toward counterpart nozzle openings on an other of the pair of liquid jet tubes; 
 inserting the jetting unit into the liquid bath with the each of the pair of liquid jet tubes positioned on opposite sides of the surface of the blisk blade and simultaneously injecting the high-pressure liquid jets from the liquid jet tubes into the liquid bath toward the opposite sides of the surface of the blisk blade to generate cavitation bubbles in the liquid bath on a periphery of the high-pressure fluid jets; 
 causing the cavitation bubbles to implode near the surface of the blisk blade to produce micro jets that create plastically formed depressions having rounded edges on the surface of the blisk blade; and 
 providing a manipulator connected to the jetting unit for positioning each of the liquid jet tubes at an equal spacing from the opposite sides of the surface of the blisk blade, the manipulator controllable to traverse the jetting unit in X, Y and Z-directions and swivel about a vertical axis and a horizontal axis with respect to the blisk blade to cause the high-pressure liquid jets to traverse a curvature of the surface of the blisk blade while maintaining the equal spacing. 
 
     
     
       2. The method of  claim 1 , and further comprising positioning and simultaneously directing the high-pressure liquid jets on the opposite sides of the blisk blade toward the blisk blade at an angle essentially normal to an adjacent portion of the surface of the blisk blade. 
     
     
       3. The method of  claim 2 , wherein the liquid is water. 
     
     
       4. The method of  claim 1 , and further comprising positioning and simultaneously directing the high-pressure liquid jets on the opposite sides of the blisk blade toward the blisk blade at an oblique angle to an adjacent portion of the surface of the blisk blade. 
     
     
       5. The method of  claim 4 , wherein the liquid is water. 
     
     
       6. The method of  claim 1 , wherein the liquid is water. 
     
     
       7. The method of  claim 6 , and further comprising providing each of the liquid jet tubes has a rectangular cross-section and includes at least one row of nozzle openings. 
     
     
       8. The method of  claim 6 , and further comprising providing that a length of the plurality of nozzle openings corresponds to a length of a portion of the blisk blade to be strengthened. 
     
     
       9. The method of  claim 1 , and further comprising providing each of the liquid jet tubes has a rectangular cross-section and includes at least one row of nozzle openings. 
     
     
       10. The method of  claim 1 , and further comprising providing that a length of the plurality of nozzle openings corresponds to a length of a portion of the blisk blade to be strengthened. 
     
     
       11. The method of  claim 2 , and further comprising providing each of the liquid jet tubes has a rectangular cross-section and includes at least one row of nozzle openings. 
     
     
       12. The method of  claim 2 , and further comprising providing that a length of the plurality of nozzle openings corresponds to a length of a portion of the blisk blade to be strengthened. 
     
     
       13. The method of  claim 4 , and further comprising providing each of the liquid jet tubes has a rectangular cross-section and includes at least one row of nozzle openings. 
     
     
       14. The method of  claim 4 , and further comprising providing that a length of the plurality of nozzle openings corresponds to a length of a portion of the blisk blade to be strengthened.